Just maybe -- think about wheels.
I grew up where the winters were just plain fierce -- actually, I just got back from there a few hours ago. The north and south shores of western Lakes Superior are beautiful much of the year, but the winter ice can really reek havoc on inland lake docks in that area.
When I was a kid we made dock ends that had old implement wheels, like those from old horse-drawn plows and hay rakes. We could pull them out in the fall, and roll them back in the spring.
We couldn't have a family get-together yesterday in Northern MN and WI because all my relatives and close friends figured it was the weekend to pull the docks, shut down the wells, and winterize the outhouses.
The newer docks in that area use commercial dock wheels from places like Mennards, Cabelas, and many other places.
Here is a link to what I'm referring to: Dock Wheels
Most are made from some pretty tough and impervious material that has a standard 1-3/4 inch diameter axle hole. They can be permanent, or they can be pulled before the ice starts to form, and put back when the ice melts for the season.
A properly built 24 to 36 foot long dock can be pushed/pulled into/out-of the water by two young guys, or five or six real strong dudes who are my age. It is even easier if you have a tractor.
In my lifetime, I've also put in a lot of docks other ways. Just yesterday, in Northern Wisconsin, I watched my nephew pushing 12-foot tamarack poles into the edge of the water in a swamp at the edge of one of his cattle pastures. He was doing with with his track hoe. He pushed them at least 6-foot into the soil with the track hoe bucket.
I've also used the "out" hose of a trash pump with pieces of pipe at the end, to make holes for poles, and then dribbled really dry concrete mix around the post when it was in place.
Cecil has put poles in during ice-over by cutting holes in the ice, and driving the poles into the pond bottoms.
There are many ways to skin a catfish.